This invention relates to arylene sulfide polymers having derivatized end-groups. In one aspect, this invention relates to poly(phenylene sulfide) having derivatized end-groups. In another aspect, this invention relates to the preparation of arylene sulfide polymers having derivatized end-groups. In a further aspect, this invention relates to the preparation of poly(phenylene sulfide) having derivatized end-groups.
Control of functionality of end-groups of arylene sulfide polymers is typically done by end-capping. In general, end-capping is accomplished by addition of an end-capping agent to the polymerization mixture at or near the end of the polymerization cycle and prior to the polymer recovery steps. The appropriate addition time is dependent on the reactivities of the starting materials and the end-capping agent and the polymerization temperature. For example, end-capping can be described as the preparation of functionalized arylene sulfide polymers by addition to the polymerization mixture of a functionalized monohaloaromatic having enhanced halide reactivity and containing the desired functional group.
However, functionalization by typical end-capping is not a viable alternative if the desired end-capping agent is unstable or reactive in the presence of water, e.g. carboxylic acid halides. Polymerization of arylene sulfide polymers occurs in the presence of water whether that water is present initially or is water that is produced during the polymerization. Since it is well known that carboxylic acid halides hydrolyze to form carboxylic acids, to obtain arylene sulfide polymers having derivatized end-groups of the desired functionality, the derivatization of the end-groups must occur in the absence of water. Therefore, the arylene sulfide polymer derivatization of the invention cannot be accomplished by practicing a typical end-capping procedure.
While arylene sulfide polymers are useful for many applications, the ability of arylene sulfide polymers to better withstand the high temperatures encountered during melt processing is desired. Arylene sulfide polymers having improved melt stability, i.e. melt processability, would be particularly useful in areas such as injection molding and coatings.
Analysis of polymer end-groups of arylene sulfide polymers is another problem which has long existed. Arylene sulfide polymers for which end-group analyses are readily obtainable would be particularly useful in determining the behavior of the arylene sulfide polymer during subsequent processing.